A plaster including a pressure-sensitive adhesive layer containing a readily dissolvable agar and at least one additive selected from the group consisting of polyacrylamides, polyvinyl alcohols, polyvinyl pyrrolidones, sodium alginate, ammonium alginate, carboxymethylcelluloses, sodium carboxymethylcelluloses, methylcelluloses, gum arabics, tragacanth gums, and xanthene rubbers, is provided.本發明係提供具備含有易溶性瓊脂，及1種以上選自聚丙烯醯胺、聚乙烯醇、聚乙烯吡咯烷酮、褐藻酸鈉、褐藻酸銨、羧甲基纖維素、羧甲基纖維素鈉、甲基纖維素、阿拉伯膠、西黃蓍膠及三仙膠所成群而形成之添加劑之黏著劑層之貼劑。
